COLUMBIA  LIBRARIES  OFFSITE 

HEALTH  SCIENCES  STANDARD 


KOCH 


:^      ^      sj:      4:      :i<:      4:      ;!;      ;fc     H' 


pidemiology  of  Tuberculosis 


ms\ 


Rcni 


KA12 


Columbia  ®ntt)mttp 

intI)e(£ilpoflfttig0rk 

CoUegc  of  ^f)j>£(iciang  anli  burgeons! 
Hibrarp 


Digitized  by  the  Internet  Arciiive 

in  2010  with  funding  from 

Open  Knowledge  Commons 


http://www.archive.org/details/epidemiol6gyoftu00koch 


■^  (^  ''^ 


EPIDEMIOLOGY  OF  TUBEECULOSIS. 


By  Robert  Koch. 


(A  lecture  given  before  the  Academy  of  Sciences  of  Berlin  at  its  session  of 
Apr.   7,   1910.)' 


Investigations  into  the  epidemiology  of  tuberculosis  have  brought 
out  some  facts  of  interest  and  also  of  practical  importance  which  will 
be  the  subject  of  the  present  paper. 

First  some  preliminary  remarks  concerning  the  character  of  the 
investigations.  They  are  in  all  essential  respects  statistical.  If  at- 
tempt had  been  made  to  cover  the  entire  field,  insurmountable  diffi- 
culties would  have  been  encountered. 

Tuberculosis,  as  is  well  known,  manifests  itself  in  the  most  varied 
ways,  frequently  occurring  in  such  insignificant  and  latent  forms  that 
no  sharp  distinction  can  be  made  between  those  affected  and  healthy 
persons.  For  that  reason  it  was  necessary  to  limit  the  present  dis- 
cussion to  a  form  that  is  sufficiently  well  marked  and  also  diagnosed 
with  certainty.  These  conditions  are  best  fulfilled  by  tuberculosis  of 
the  lungs,  the  so-called  pulmonary  consumption.  This  form  is  also 
to  be  recommended  for  such  investigations  because  it  is  by  far  the 
most  frequent,  the  one  chiefly  concerned  in  disseminating  tuber- 
culosis and  therefore  the  most  important  in  medical  practice. 

A  still  further  limitation  must  be  made.  Owing  to  the  long  dura- 
tion of  pulmonary  consummation  and  the  difficulty  of  making  sharp 
distinctions  as  to  its  beginning,  we  must  disregard  the  statistics  of 
illness  from  this  disease  and  consider  only  the  statistics  of  death. 
In  these  we  have  original  data  that  are,  to  a  certain  extent,  trust- 
worthy, and  that  may  serve  as  a  basis  for  investigation. 

It  is  true  that  this  trustworthiness  could  only  be  absolutely  as- 
sured if  in  every  case  of  death  by  pulmonary  consumption  the  diag- 
nosis were  confirmed  by  an  autopsy  made  by  a  competent  expert, 

1  According  to  a  manuscript  kindly  placed  at  the  disposal  of  the  editor  of  the  Zeit- 
schrift  fiir  Hygiene  und  Infections-krankheiten  after  the  death  of  the  author.  Translated 
from  Zeitschrift  fiir  Hygiene,  Leipzig,  1910,  vol.  67,  Part  1,  pp.  1-18. 

659 


Jfiti¥ifdvfn  front 


660  ANNUAL,  KEPORT   SMITHSONIAN   INSTITUTION,   1910. 

which  by  no  means  really  occurs.  Autopsies  are  held  only  in  a  small 
proportion  of  cases,  and  therefore  some  uncertainty  exists.  Besides 
this,  in  many  regions,  even  in  entire  countries,  there  is,  for  well- 
recognized  reasons,  a  certain  hesitation  attached  to  pronouncing  a 
diagnosis  of  pulmonarj^  consumption,  and  the  disease  is  called  in- 
stead chronic  catarrh  of  the  lungs,  or  something  similar.  It  is,  there- 
fore, not  al\\'ays  admissible  to  compare  with  each  other  the  death 
rates  of  pulmonary  consumption  of  different  countries  without  fur- 
ther examination,  and  it  is  to  be  supposed  that  many  cases  of  strik- 
ing differences  may  be  explained  by  circumstances  of  this  kind. 
This  source  of  error  has,  however,  no  essential  influence  when  we  con- 
sider the  increase  or  decrease  of  mortality  in  the  same  country  or  city. 

On  the  other  hand,  it  YasLj  be  said  that  pulmonary  consumption 
is  a  very  satisfactory  subject  for  statistical  investigation,  because 
its  characteristic  symptoms  make  its  diagnosis  quite  certain,  even  by 
the  laity,  so  that  for  many  matters  where  absolute  exactitude  is  not 
required,  data  are  available,  even  though  not  supported  by  medical 
authority  or  by  autopsies. 

If  in  an  investigation  of  the  epidemiology  of  tuberculosis  we  go 
back  to  early  data  concerning  mortality  from  consumption,  we  find 
the  disease  mentioned  in  the  oldest  records. 

In  the  writings  of  Hippocrates  a  very  characteristic  description 
of  pulmonary  consumption  is  given,  and  we  may  conclude  from  it 
with  certainty  that  the  physicians  of  that  time  were  quite  familiar 
with  the  symptoms  of  the  disease.  It  is  stated  in  several  places  that 
numerous  persons  have  been  affected  by  it.^  We  must  therefore  con- 
clude that  phthisis  already  at  that  time  played  a  part  smiilar  to  that 
which  it  assumes  at  the  present  day. 

We  find  the  first  numerical  data,  however,  much  later,  and  these 
relate  to  Sweden,  where  they  were  collected  by  the  clergy. 

From  these  we  obtain  the  highest  figures  which  mortality  from 
phthisis  has  hitherto  reached  (Table  1).  About  the  middle  of  the 
eighteenth  century  the  mortality  in  Sweden  was.  for  the  country, 
21.5  per  10,000  persons,  and  it  rose  very  slowly  to  27.7  about  1830. 

iFrom  the  writings  of  Hippocrates  (Grimm's  translation).  On  Epidemics,  p.  16: 
"  For  consumption  alone,  as  the  most  important  single  disease  among  those  prevailing 
at  that  time,  killed  many  people "  ;  p.  57 :  "  The  greatest  and  most  terrible  disease, 
and  the  one  which  was  the  most  fatal,  was  pulmonary  consumption." 


EPIDEMIOLOGY   OP   TUBERCULOSIS KOCH. 


661 


Table  1. — Mortality  fro?n  pulmonary  consumption. 
[After    Sundbarg.     Calculated    for    every    10,000    persons.] 


In  Swe- 
den. 

In  Stock- 
holm. 

1751-1760  

21.5 
20.6 
20.8 
23.1 
24.0 
25.1 
26.9 
27.7 
(a) 
30.6 
32.4 
30.0 
27.0 

73  2 

1761-1770 

69  8 

1771-1780 

74  4 

1781-1790 

87  7 

1791-1800 

85  0 

1801-1810 

83.7 

1811-1820  

87.2 

1821-1830  

93.1 

1831-1860 

(a) 

1861-1870 

43  3 

1871-1880 

40  6 

1881-1890 

34  6 

1891-1900 

29.2 

«  No  data  given. 

Considerably  higher  figures  prevail  in  the  chief  city  of  the  country, 
and  this  corresponds  to  the  usually  accepted  opinion  that  the  cities, 
on  account  of  the  crowded  buildings  and  the  bad  dwelling  conditions 
connected  therewith  and  also  because  of  the  less  resisting  power  of 
their  inhabitants,  are  more  unfavorably  situated  as  regards  tubercu- 
losis than  is  the  open  country.  Stockholm  had  in  1750  a  mortality 
of  73.2,  which  in  1830  had  advanced  to  93.1;  that  is  to  say,  nearly 
100  per  10,000,  or  1  per  cent. 

The  increase  of  mortality  from  phthisis  in  Stockholm  is  said  by  the 
Swedish  physicians  to  be  caused  by  the  misuse  of  alcohol.  The  rate 
of  100  per  10,000  is  only  met  with  where  the  most  unfavorable  sani- 
tary conditions  are  encountered,  for  example,  in  jails,  at  least  in 
former  times ;  and  also  among  the  perishing  races  of  North  American 
Indians  where  alcohol  is  also  the  principal  cause  of  decay.  Accord- 
ing to  the  concurrent  testimony  of  various  travelers,  the  inhabitants 
of  Greenland,  compelled  by  the  northern  climate  to  live  crowded  to- 
gether in  their  huts,  thus  gTeatly  increasing  the  possibility  of  infec- 
tion, suffer  in  an  extraordinary  degree  from  tuberculosis,  reaching,  it 
appears,  even  a  higher  figure  than  100  per  10,000. 

A  death  rate  of  50  per  10,000  occurs  rather  frequently  in  the  last 
quarter  of  the  nineteenth  century,  especially  in  cities.  I  will  cite  as 
examples  among  the  German  cities:  Dllsseldorf,  55;  Elberfeld,  59; 
Osnabriick,  52;  Cologne,  50^;  Munich,  50.  Especially  high  figures 
occur  in  Austria-Hungary  where  there  is  50  for  Buda-Pesth ;  58  for 
Presburg ;  66  for  Fiume ;  72  for  Vienna. 

From  these  figures  we  have  a  gradual  descent  until  we  reach  a  total 
absence  of  mortality.    In  certain  regions,  as  in  central  Africa,  tuber- 


662  AXXUAL,  EEPOET   SMITHSOXIAX   IXSTITUTIOX,   1910, 

culosis  occurs  only  in  C|uite  isolated  cases,  the  patients  being  of  Euro- 
j)eaii  or  coast  origin.  At  the  present  time  the  lowest  figure  for  some 
regions  in  Australia  is  about  7  deaths  per  10.000.  But  this  figure 
is  also  reached  in  some  sections  of  our  own  country,  as  for  example,  in 
the  district  of  Osterode  in  the  Province  of  Allenstein. 

Such  low  death  rates  have  only  been  observed  during  the  last  few 
years,  and  this  leads  me  to  the  most  notable  phenomenon  in  the  epi- 
demiology of  tuberculosis,  to  which  I  would  esj^ecially  invite  your 
attention,  namely,  the  almost  universal  marked  decrease  in  pulmonary 
consumption  which  has  become  evident  during  the  last  30  or  40  years. 

The  lowering  of  the  death  rate  began  first  in  England,  and  it  also 
happened  that  the  English  hygienist  Farr  was  the  first  who  was 
struck  by  this  and  who  called  attention  to  it.  In  our  own  country 
Hirsch.  the  author  of  the  well-known  Handbook  of  Historico-geo- 
graphical  Pathology,  was  the  first  to  mention  it. 

This  remarkable  phenomenon  was  at  first  received  with  great  scep- 
ticism, and  it  was  alleged  that  there  were  either  errors  in  the  statistics 
or  that  it  depended  upon  the  decrease  in  the  general  death  rate  which 
had  been  previously  noted,  though  not  to  the  same  clegTee.  But  as 
the  decrease  in  pulmonary  constmiption  was  sliown  to  occur  almost 
universally  and  also  continued,  there  remained  nothing  to  do  but  to 
acknowledge  it  as  a  fact  and  to  find  an  explanation  therefor. 

In  order  to  give  an  idea  of  the  decrease  of  consumption,  the  course 
of  the  death  rate  from  that  disease  in  the  Kingdom  of  Prussia  may 
serve  as  a  specially  characteristic  example. 

It  is  shown  graphically  by  a  curve  in  Table  2.  Up  to  the  year 
1886  the  figures  representing  the  mortality  remain  with  irregular,  but 
not  marked  variations  a  little  above  30,  then  begins  a  decrease  which 
has  kept  up  with  but  little  variation  to  the  present  time.  In  the  year 
1908  the  figure  fell  to  16.2-1,  a  decrease  of  nearly  50  jper  cent. 

For  the  German  Empire  the  statistical  records  do  not  go  back  far 
enough  to  demonstrate  the  reduction  in  consumption  in  a  similar 
manner.  Yet  the  curve  for  all  Germany  resembles,  as  far  as  it  goes, 
that  for  Prussia ;  it  is  somewhat  higher,  because  the  States  of  southern 
Germany  are  not  as  favorably  situated  as  Prussia  with  regard  to  the 
disease. 

The  significance  of  this  reduction  in  consumption  will  be  noted 
when  we  observe  that  if  the  same  relations  prevailed  now  as  30  years 
ago  about  100,000  more  persons  wotild  die  annually  of  consumption 
than  is  now  actually  the  case.  It  is  therefore  very  important  for  us 
to  ascertain  the  causes  for  this  decrease,  in  order  to  know  whether  it 
is  subject  to  any  influence  under  our  control:  whether  it  wotild  be 
possible,  were  it  arrested,  to  overcome  the  obstacle,  also  whether  it 
would  be  practicable  to  hasten  its  decline  beyond  the  present  rate. 


EPIDEMIOLOGY  OE   TUBERCULOSIS — KOCH. 


663 


The  question,  therefore,  arises  as  to  what  is  the  cause,  or  rather 
what  are  the  causes  of  this  decrease,  for  it  can  hardly  be  supposed 
that  it  depends  on  a  single  factor  alone. 

Concerning  this  it  might  at  first  be  supposed  that  the  death  rate 
from  consumption  decreases  because  the  general  death  rate,  as  is  well 
known,  is  also  decreasing.  This  need  not  necessarily  be  so,  for  it 
would  only  occur  in  case  the  causes  which  influence  the  general  death 

Table  2. — Mortality  from  consumption  in  Prussia. 


I 


?  5  9tfA'  ?  3  H  5  &  ?  5-'A^i  2  3  ^  5  G  ?  8  9>yi'  2  5  H  5  H  5  9 


_j_j 


0"W 


rate  have  a  similar  influence  upon  the  death  rate  from  consumption. 
But  we  now  see  that  the  decrease  in  the  latter  is  much  more  rapid  than 
that  of  the  general  mortality,  this  being  more  probably  influenced  in 
a  considerable  degree  by  the  decrease  in  pulmonary  consumption. 
Therefore  that  disorder  must  be  influenced  by  factors  peculiar  to 
itself. 

It  might  also  appear  possible  that  the  decrease  in  tuberculosis 
depends  upon  the  general  epidemiological  course  of  this  disease;  that 


664 


AlSToS^UAL   EEPOET    SMITHSOXTAX    IXSTITUTIOX,   1910. 


tliis  epidemic  in  itself,  lilve  other  epidemics,  such  as  the  plague  and 
cholera,  must  decrease  after  a  certain  lapse  of  time. 

If  this  were  its  natural  course  then  the  decrease  would  proceed 
ereryTrhere  in  a  uniform  manner.    But  this  is  by  no  means  the  case. 

Table  3. — Mortality  from  consumption  in  Massachusetts,  Japan,  Great  Britain, 

and  Norway. 


,  4 


moi  ii  w  ri,  J^'  y'.  ^^  01 


^r,.:... 


\ 


30 


\ 


,€  /70/?5  m  /^  /^  1%  m  m 


In  most  countries,  it  is  true,  the  curve  descends,  but  there  are  others 
in  which  it  rises.  It  ^A'ill  be  seen  by  consulting  Table  3  that  England, 
Scotland,  and  the  American  State  of  Massachusetts  (chosen  because 
its  statistics  reach  far  enough  back)  have  a  decreasing  death  rate 
from  consumption,  while  in  Ireland,  Xorway,  and  Japan  it  is  increas- 


EPIDEMIOLOGY   OF   TUBEECULOSIS KOCH. 


665 


Table  4. — Mortality  from  consumption  at  Paris,  Hamburg,   Copenhagen,  and 

London. 


^:%%%:%% 


?la«(f«rtaHf  !ip  iftj 


•x 


1 


f$a.    <ik,\Ji,    A    &1/    &6,    %  .^  M 


666 


Al^'XUAL  REPOET    SMITHSOXIAN   INSTITUTION,   1910. 


ing.  We  meet  with  the  same  phenomenon  in  certain  cities;  so  London, 
Coi^enhagen,  and  Hamburg  have  curves  of  decrease,  while  Paris,  on 
tlie  contrary,  has  a  liigh-Iying  curve  wliicli  sliows  but  little  tendency 
to  descend  (Table  4). 

Table  5. — ILortality  froiu  cousumijtion  at  Hamlurg. 


7   $  pA\  S  1>  U-»  ?  g5^4-S-->-V$-4  T  S-^l&grS-^S^  J;gVyi  'r^V5-t 


n 


H  !>  M  S 


=1* 


3  5't  3s-lS9M\^":>H  5t  ?  Snw  iihS 


w 


France  has  a  death  rate  from  consumption  that  is  especially  un- 
favorable. In  cities  of  more  than  5,000  inhabitants,  the  only  ones 
for  which  statistics  are  available,  27  out  of  every  10,000  persons  die 
of  this  disease,  and  there  was  no  decrease  in  the  years  from  1901  to 
1906  (so  far  as  the  data  have  been  published). 


EPIDEMIOLOGY   OF   TUBERCULOSIS KOCH. 


667 


Very  characteristic  examples  of  favorable  indications  in  the  mor- 
tality of  consumption  are  shown  by  Hamburg  (Table  5)  and  Boston 
(Table  6). 

Before  1860  Hamburg  lost  by  consumption  37  for  every  10,000 
inhabitants,  and  in  1880  the  figure  stood  at  33.5.  In  1907  the  mor- 
tality had  decreased  to  13.7. 

Boston  had  in  1886  a  mortality  of  about  40,  in  1907  it  was  18.5. 

Table  6. — Mortality  from  consumption  at  Boston. 


yjJ  »,  «  »?  St^'l  i  -V  U  T  »  1i}\  J .  ^  5  f  7  s|yi  l^-i  ',,i.l  5^1 1)  3,J-,v  i  f)|i^ji  M  ?r :  i^ll^i ;  J 


15 


if 


1l 

>^ 

,9 

J 

■  t) 
i\ 

ii 

V 

\i 

1$ 


''^  =  -  ^  -  ■^^'- ^^ '♦•''-^f  J'.  .H?!!^2  J"!  HiS'W':?^  Ut'ji^lO^'^ '►'^ 


These  figures  are  still  more  sigTiificant  if  we  compare  them  with 
those  of  cities  which  are  exposed  to  conditions  similar  to  those  of 
Hamburg  and  Boston.  For  this  purpose  we  will  compare  Hamburg 
with  Berlin  (Table  7)  and  Boston  with  New  York  (Table  8). 

The  mortality  curves  of  Hamburg  and  Boston  descend  at  once  and 
the  decrease  continues  at  a  uniform  rate,  while  in  Xew  York  and 
especially  in  Berlin  it  has  slackened  for  several  years  past. 

The  examples  I  have  submitted,  and  which  might  easily  be  in- 
creased in  number,  show  that  there  can  be  no  question  of  a  general, 


668 


ANNUAL  REPORT   SMITHSOXIAX    IXSTITUTIOX,   1910. 


regular,  uniform  decrease  in  mortality  from  consumption,  and  that 
"sve  must  therefore  seek  for  other  factors  than  those  dependent  on  a 
spontaneous  cause  of  decrease  connected  with  the  epidemiological 
course  of  the  disease. 

Table  7. — MortaJiti/  from  consumption  at  Berlin. 


)l2Sff76TS9^23H56TS9^g3H^fa 


M 


tfa 


15 


r3  - 
II- 


I0aii^^|$rslf()is infiis-^^  2  5  v5*r«9|0 


It  might  be  alleged  that  the  rirulence  of  tuberculosis  has  abated. 
But  in  reply  to  this  it  should  be  said  first  that  the  decrease  in  tuber- 
culosis began  quite  suddenly,  and  after  a  few  decenniums  has 
reached,  in  many  cases,  60  per  cent  and  over.    As  the  mortality  from 


EPIDEMIOLOGY   OF   TUBERCULOSIS KOCH. 


669 


consumption  has  been  marked  and  often  slowly  increasing  during 
2,000  years  it  is  not  reasonable  to  suppose  that  it  would  decline  all  at 
once  without  any  assignable  cause.  Besides,  the  decrease  of  viru- 
lence would  first  be  manifested  by  an  amelioration  in  single  cases 

Table  8. — Mortality  from  consumption  at  New  Yorlc. 


O'''.0jB-O~O—Ct—O—O — b — o 


which  would  also  more  frequently  terminate  in  recovery.  But  noth- 
ing of  this  kind  occurs.  '  It  is  indeed  true  that  in  modern  times  great 
advances  have  been  made  in  the  treatment  of  tuberculosis,  and  that 
we  succeed,  through  the  so-called  hygienic-dietetic  treatment  and 


670  A3SranrAL  EEPOET    SiHTHSOlSTA^  IirSTITUTI03Sr,  1910. 

especially  by  tlie  specific  treatment,  in  curing  many  cases.  At  pres- 
ent, however,  only  a  comparatively  small  percentage  of  cases  sliare 
this  advantage,  and  for  the  cases  not  so  treated  we  are  unfortunately 
convinced  again  and  again  that  pulmonary  tuberculosis  maintains 
the  same  deadly  characters  as  formerly.  Besides  the  decrease  in  con- 
cur:.: rir.r.  had  already  been  going  on  for  several  years  before  the  new 
m-ih^  h  01  treatment  had  l^een  widely  dissemmated. 

The  decrease  in  consumption  has  often  been  ascribed  to  the  dis- 
covery of  the  i;oercle  bacillus.  It  has  been  said  that  by  this,  the 
infec'tious  ;::.. racier  of  the  disease  was  proved  and  that,  in  conse- 
quence of  this,  people  became  more  cautious  and  avoided  infection 
as  much  as  possible,  while  previously  physicians  did  not  admit  the 
infectiousness  of  consumption  and  the  public  at  large  followed  them 
in  this  as  a  matter  of  course. 

There  is  certainly  much  to  be  said  for  this  argument.  In  any 
case  it  is  very  striking  that,  with  a  few  exceptions,  the  decrease  in 
consumption  set  in  everywhere  within  a  few  years  after  that  dis- 
covery. Yet  the  exceptions  prove  at  once  that  this  new -bom  fear 
of  infection  is  not  the  only  factor  involved,  although  we  must  allow 
to  it  a  certain  influence  which  is  by  no  means  slight, 

German  authors  have  frequently  claimed  that  social  regulations, 
particularly  insurance  against  illness,  has  had  an  effect  upon  the 
decrease  of  tuberculosis.  To  a  certain  extent  this  is  undoubtedly 
true,  particularly  as  regards  present  conditions  in  Germany;  yet  in 
most  other  countries,  where  such  regulations  have  not  yet  been  estab- 
lished, the  decrease  has  been  just  as  great  and  has  been  going  on  at 
the  same  time,  so  these  regulations  can  not  be  with  us  the  most 
weighty  cause. 

It  would  take  me  too  long  to  enumerate  and  discuss  all  the  attempts 
at  ex]Dlariaticai  that  have  been  made,  and  I  will  therefore  confine 
myself  in  conclision  to  those  investigations  of  this  question  which 
appear  lo  ne  i  :>  l^e  of  the  most  importance.  These  investigations 
were  suggested  by  the  striking  fact  that  the  death  rate  from  tuber- 
culosis shows  great  differences  in  the  three  countries  belonging  to 
Great  Britain.  In  England  and  Scotland  it  is  decreasing.;  in  Ire- 
land, on  the  contrary,  it  is  slowly  but  evidently  increasing.  News- 
holme,  the  well-known  medical  statistician,  has  endeavored  to  find 
the  prime  cause  of  this.  With  the  greatest  thoroughness  he  has  ex- 
amined all  the  factors  in  the  question,  chiefly  lodging,  food,  condi- 
tions '.f  i^ervice.  care  of  the  sick,  emigration,  and  has  finally  become 
convinct-rl  that  for  Ireland  the  method  of  caruig  for  the  sick  is  the 
determining  factor.  "While  in  England  and  Scotland  phthisical 
charity  patients  are  committed  to  isolated  institutions,  in  Ireland 
they  are  supported  without  being  required  to  place  themselves  in 
an  institution :  they  therefore  remain  in  their  own  lodgings  and  con- 


EPIDEMIOLOGY   OF    Tr'BEECULOSIS KOCH.  671 

tinue  to  spread  infection  about  them.  Xewsholme  endeavors  also  to 
prove  that  in  Norway,  too,  the  mortality  from  consumption  is  on  t?ie 
increase  because  insufficient  care  is  taken  for  the  placing  of  phthisical 
patients  in  hospitals.  I  might  remark  here  that  in  Norway  this 
defect  has  already  been  recognized  and  care  has  been  taken  to  remedy 
it  by  founding  sj)ecial  hospitals  for  consumptives.  It  appears  that 
on  account  of  this  precaution  the  mortality  curve  in  quite  recent 
years  no  longer  ascends.  Newsholme  sajs  further  that  the  very  high 
mortality  in  Paris  results  from  the  insufficient  hospital  facilities,  in 
consequence  of  which  patients  are  not  kept  in  long  enough  to  insure 
protection  of  others  against  infection. 

With  reference  to  this  I  entirely  agree  with  Newsholme  that  a 
commitment  to  hospital  for  as  long  a  time  and  with  as  careful  atten- 
tion as  possible  is  the  most  effective  means  of  preventing  infection 
and  thereby  the  spread  of  consumption.  My  experience  also  shows 
that  wherever  consumptives  are  kept  in  sufficient  numbers  in  hospi- 
tals there  consumption  is  most  diminished,  and  vice  versa.  It  is 
also  ap]3arent  that  in  no  way  can  the  danger  of  infection,  which 
attends  every  phthisical  patient,  be  so  successfulh*  combated  as  by 
isolation  in  a  hospital.  The  value  of  hospital  isolation  is  shown  in 
a  striking  manner  by  such  treatment  of  leprosy,  as  by  its  means  we 
have  attacked  that  disease  with  good  results. 

Besides  this  factor  there  is  still  a  second  one  that  plays  a  very 
important  part.  This  is  the  housing  of  patients.  The  more  con- 
tracted this  is — the  more  lack  there  is  of  light  and  air — the  more  is 
infection  favored.  By  many  authors  poverty  and  density  of  popu- 
lation have  been  mentioned  as  having  a  decided  effect  on  the  fre- 
quency of  phthisis,  and  quite  correctly  so;  but,  in  truth,  this  is 
caused  by  the  defective  and  too  small  dwellings  in  which,  through 
poverty  and  the  increased  density  of  population,  people  are  forced 
to  live.  I  might  even  go  a  step  further  and  say  that  it  is  not  so  much 
the  contracted  character  of  the  d'^^'ellings  as  a  whole  as  the  condition 
of  the  sleeping  rooms  that  favors  infection.  Even  in  a  spacious 
dwelling,  in  itself  hygienic,  the  danger  of  infection  may  become 
very  great  if  the  inhabitants  crowd  together  at  night  in  a  small 
sleeping  room.  It  is  certainly  not  an  accident  that  with  us  the 
highest  mortality  from  consumption  is  not  found  in  the  poor  regions 
of  the  eastern  provinces,  but  in  the  relatively  prosperous  and  amply 
cultivated  regions  along  the  coast  of  the  North  Sea,  where  from 
olden  times  the  evil  custom  has  prevailed  of  using  for  sleeping 
rooms  small,  cell-like  apartments  built  in  the  wall,  the  so-called 
cubbies  (Butzen) .  which  are  shut  up  at  night,  and  that  in  the  north- 
ern parts  of  Sweden,  with  a  climate  that  is  notoriously  healthy,  the 
highest  death  rate  for  consumption  occurs  where  people  also  sleep 
in  closets  quite  similar  to  the  cubbies  of  Frisia. 


672 


ANNUAL,  REPOET   SMITHSONIAN   INSTITUTION,   1910. 


The  striking  fact  that  with  us  the  cities  often  have  a  lower  con- 
sumption death  rate  than  does  the  surrounding  country  is  apparently 
due  partly  to  the  want  of  hospitals  and  partly  to  the  bad  habits  of  the 
rural  inhabitants,  in  that  they,  even  when  they  have  at  their  dis- 
posal several  living  rooms,  select  the  meanest  and  smallest  for  a 
sleeping  room.  As  an  example  of  the  distinction  between  city  and 
country,  the  following  statistics  for  certain  Prussian  provinces  may 
serve  (Table  9)  : 

Table  9. — Mortality  from  pulmonary  consumption  per  10,000  inhaMtawts. 
[Aftei-  Hirsch,  Historico-Geographic  Pathology.] 


Province. 


In  the 
city. 

In  the 
country. 

25.4 

13.5 

23.9 

14.1 

24.9 

15.5 

31.3 

18.5 

26.9 

27.0 

37.3 

27.5 

33.8 

44.4 

48.7 

52.2 

47.6 

53.4 

Marienwerder 

Danzig 

Konigsberg  . . . 

Bromberg , 

Erfurt 

Breslau 

Hannover 

Osnabriick 

Cologne 


But  in  cities,  also,  housing  conditions  are  poor.  There  are  numer- 
ous dwellings  that  consist  of  a  single  room,  in  which  families,  often 
with  several  children,  live,  cook,  and  sleep,  often  in  a  single  bed. 
According  to  Rubner  there  are  in  Hamburg,  Berlin,  and  Breslau 
10  to  14  per  cent  of  overcrowded  dwellings,  if  we  consider  as  such  a 
room  with  but  one  window  housing  more  than  5  persons. 

Ka^^serling  has  estimated  that,  of  the  phthisical  patients  who 
die  in  their  own  rooms  40.6  per  cent  inhabit  but  one  room,  41.7  per 
cent  but  two  rooms;  that  in  Berlin,  during  three  years,  8,229  per- 
sons were  exposed  to  the  greatest  danger  of  infection  because  of  con- 
sumptives dying  in  one-room  dwellings.  It  is  well  known  that  con- 
sumptives in  the  last  stages  of  the  disease,  when  they  are  helpless 
and  expectorate  sputum  crowded  with  tubercle  bacilli,  are  especially 
liable  to  spread  infection. 

If  we  adhere  to  the  view  that  the  most  effective  protection  against 
infection  is  the  isolation  of  consumptives  in  hospitals,  and  then 
reflect  further  that  the  number  of  such  adult  persons  for  which,  on 
account  of  tuberculous  disease,  hospital  treatment  is  necessary, 
amounts  in  the  German  Empire  to  from  150,000  to  200,000  annually, 
and  that  it  is  quite  impossible  to  place  these  all  in  hospitals,  nothing 
else  remains  but  to  isolate  the  greater  part  of  them  in  their  own 
dwellings.  If  it  were  possible  to  assign  to  each  patient  a  separate 
sleeping  room,  this  might  be  to  some  extent  effected ;  but  how  can  it 
be  done  if  the  entire  dwelling  consists  of  only  a  single  room  ? 


EPIDEMIOLOGY   OF   TUBERCULOSIS KOCH.  673 

These  considerations  show  that  the  decrease  in  consumption  in 
recent  times  depends  upon  various  factors,  of  which  the  two  most  im- 
portant ones  are  the  care  of  those  affected  by  isolating  them  in  hos- 
pitals and  the  improvement  of  housing  conditions,  especially  as 
regards  the  sleeping  rooms. 

It  is  apparent  from  this  that  vast  obstacles  have  yet  to  be  over- 
come before  we  can  succeed  in  reducing  still  lower  the  mortality 
from  consumption,  and  finally  reach  a  level  which  will  possibly  be 
below  the  lowest  existing  at  the  present  time,  namely,  T  per  10,000 
persons. 

We  are  now  enabled  to  realize  the  great  benefit  that  accrues  from 
having  an  exact  knowledge  of  the  statistics  of  mortality  from  con- 
sumption in  countries  and  cities.  The  mortality  curve  informs  us 
at  once  whether  the  conditions  are  favorable  or  unfavorable,  whether 
the  mortality  is  decreasing  and  the  measures  taken  are  still  effective, 
or  whether  improvements,  supplementary  regulations,  etc.,  should  be 
instituted.  So  in  Norway  the  course  of  the  consumption  curve 
induced  the  authorities  to  take  in  hand  the  building  of  hospitals,  and 
thus  cause  it  to  descend. 

New  York  resolved,  as  soon  as  it  was  shown  that  the  curve  began 
to  flatten  and  show  greater  variations,  to  take  more  care  of  the  sick 
and  to  increase  the  number  of  beds  assigned  to  consumptives  from 
2,500  to  6,000.  In  Berlin,  for  the  same  reason,  there  was  erected  a 
special  hospital  for  pulmonary  consumptives,  with  1,000  beds. 

It  is  very  desirable  that  exact  mortality  statistics  should  be  every- 
where obtained  and  that  studies  of  the  same  should  be  extended  to 
smaller  and  smaller  districts,  so  as  to  ascertain  more  fully  the  con- 
ditions that  control  the  development  of  tuberculosis,  especially  in  the 
case  of  small  hamlets  and  country  districts,  and  thereby  to  relieve 
them. 

In'  our  own  country  statistics  are  already  developed  far  enough  to 
enable  us  to  scan  the  death  rate  from  consumption  in  single  districts. 
1  have  here  the  record  of  mortality  in  two  departments,  which  ex- 
emplifies in  a  striking  manner  the  interesting  problems  that  result 
from  a  comparison  between  different  districts.     (Table  10.) 

Table  10. — Deaths  from   tuberculosis  in  1907  per   10,000  inhaUtants. 

AUenstein  department  (10.33)  : 

OsterodeJ 7.2 

Joliannisburg 7.  7 

Sensburg 8.  5 

Neidenburg 9.  5 

Rossel 30.0 

Ortelsburg 11.0 

Lyck 11.5 

Lotzen 11-  5 

AUenstein 13.  0 

97578°— SM  1910 43 


674  AXXUAL   EEPOET    SMITHSONIAN    INSTITUTIOiSr,    1910. 

Osuabriick  department  (23.34)  : 

Osnabriick    (country) 15.0 

Iburg 17.0 

Osnabriick  (city) 18.0 

Meppen ^ 22.8 

Melle 24.0 

Ascbendorf 24.0 

Grafscbaft  Beutbeim 25.  75 

Bersenbruck , 28.0 

Lingen 30.  0 

Wittlage 30.0 

Hiimmling 35.  0 

For  an  effective  campaign  against  tuberculosis  it  would  be  necessary 
to  go  still  further  and  divide  each  district  into  smaller  areas,  each  of 
which  should  be  specially  investigated  and  provided  with  detention 
houses  or  other  devices  for  combating  the  disease. 

The  statistics  of  mortality  and  the  ej^idemiological  researches  con- 
nected therewith  constitute  an  important  feature  of  the  measures  by 
which  tuberculosis  is  to  be  combated. 


DATE  DUE 


>  ^  3  1999 


S«lMl    t- 


H.Vf  2  i} 


891 


<i»»4^ 


RARY 

-r,  or  at  the 
t)orrowin? 


COLUMBIA  UNIVERSITY  LlBRAm^^ 


0037575880 


EC  311 
Koch 

Ed  id  ern  t  nl  n  cv    of>    a-,:,-u. 


K812 


